The MK I takes a single 6922 tube. I've experimented with several, and here are my impressions, FWIW:
1) Siemens--Smooth, detailed, tight and accurate bass. I tried a Siemens CCa (pricey little things), and in this application I would not spend the extra money. For around $55, we bought the tube that has remained in the amp for around six months thus far.
2) Amperex USA PQ--A little more bloomy in the bass, not quite as detailed. Seemed like it would be better in a bigger room, I don't know.
3) Mullard--Smooth, laid back, probably my favorite tube for jazz/classical/vocals.
You can easily remove the case screws with a number 2 allen key. Gently remove the tube, and replace it with an NOS of your choice. The difference will be quite noticeable. The tube should last around 10,000 hours, according to the manufacturer.
The amp also benefits from an upgraded power cord. I'm using a Van Den Hul Mainstream Hybrid, but there are numerous cords out there. In the case of this amp, our $125 VDH sounded just as good as an $800 cord we tried, which actually ended up on our all tube SET amp.
Finally, the amp needs about 30 minutes to warm up. Until then, it will sound a bit thin, especially in the bass response.
The MKI has a pre/sub out, so it's pretty versatile.
Enjoy, and please post your impressions afterwards. Or write me directly if you just can't stand the thing! I doubt that will be the case.
All the best,
Thanks for the help. I ordered a Mullard 6922 from the early 70's. I'll be using a shunyata power cord.
P.S. Do you remember how much break in time yours needed? Any reccomendations on how to break it in? Leave it on all the time?
I bought mine used, so I'm guessing that it was already broken in. If you are listening often enough, I'd just leave it on all the time. Great tube, and great power cord.
The most fun I've had in this hobby is being surprised. If your CD player allows for it, try running the Prima as an amp only (pre-out), and then as an integrated. We just discovered a big difference in the sound, and one way worked well when the system was in one room, and the opposite in another. Go figure.
Lousey, sounds like you have the same amp as I have. Great amp all around. Go with the Mullard ECC88 gold pin tube. As Boa2 suggested, the VDH cord works great with the amp. If you can, get the Cardas posts, rcas and the Kimbar caps installed. This will also make a change for the better.
I also bought mine used about 3 years ago. I usually left it powered on on the mute select unless I knew I would be away for a couple of days or so. Leaving it on, with proper venting was never a problem. For a cheap tweek, mass load the top to reduce vibration and put some cones or 3 HRS feet underneath.
As Boa2 suggested, you can use this amp as a power amp, preamp or leave it as a int. amp. Happy listening.
Hi Eldelucesol, thanks for the advice. I'm pretty sure the Mullard that I put in there was gold pin. Also, I haven't done any mods on the amp, and I noticed that there are already Kimber Kaps installed. Could they have added that in a later production run?
What exactly is mass loading? Putting something heavy across the top?
Hi, I am really interested on this amp since I am considering buying it. I really appreciate all your comes since I am pretty new myself to the hi-fi world.
One question, I have been told that this amp has a very low Signal Noise To Ration (70db) - whatever that is... - How important is this feature? I checked other amps (i.e. Kora or Krell) and they seem to deliver higher SNRs. any thoughts? Thanks!
Krell and Audio Aero are at the two opposite ends of the audio spectrum. The Audio Aero is a hybrid tube amp, and the Krell is pure solid state. It really depends what you're looking for.
The Audio Aero's SN ratio isn't that high. But it doesn't bother me, not for a second. There are some, though, for whom it might be a deal breaker. It really just depends on your taste and your setup.
Personally, I don't like most of what Krell has to offer. It's too clinical for me. Some don't like what Audio Aero has to offer, because it's too euphonic, or too whatever. I've never heard Kora.
The Audio Aero is very, very musical, and at the price I think it's hard to beat. Also, it benefits from tube rolling greatly.
Hi, thank you very much for your comments. Actually, I do agree that the Krell or the McIntosh sound really too "electric". I really like the sound of valve amps. (Never heard a hybrid...)
I just bought a pair of Triangle Antal XS and I think they would match well with a low powered hybrid. Forgive my ignorance but to be honest I wouldn't know how to connect the Antal with this, since each speaker has four speaker posts whereas the amp only has two per speaker. Can you please tell me how to hook them up? Any advice on which cables should I get?
Oh, and forgot. One last question. Is this amp well serviced in the US?
Thanks again for the patience! Josep
We bought my AA Prima hybrid after hearing it with a pair of Triangle speakers. Although I find that the Triangles can be somewhat bright, if you end up with a Prima Hybrid MKI, you will likely want to experiment with different 6922 tubes, as they will help 'tune' the sound to the balance that you desire. The MKII version of this amp has a hardwired miniature 6021W tube. It also has remote control, and is 50W (as opposed to the 40W of the MKI), but it does not have a preamp out like the MKI. In other words, you can use the MKI as a preamplifier with any type of amp/monoblocks that you like.
Your four binding posts mean that you can bi-wire your speakers. That is, you can buy a pair of speaker cables that has two terminations on the amp end, and four on the speaker side. Your binding posts should presently have a metal plate of some type between them, and if you run single wire speaker cable you will want to connect the cables to the binding posts on the bottom. You can also try using jumpers, which are short cables that replace those metal plates for better conductivity. Many options are available, and one will sound best to you. If I'm not mistaken, those speakers take some time to break in. If they are not yet broken in yet, you might want to let them do so before tweaking your cables, etc. too much. Copper cables tend to give you a warmer sound. While my preference is for silver, I think you might find silver to be too bright with the Triangles. If so, make sure your room is treated before making conclusions.
Finally, Globe Audio Marketing is the NA rep for Audio Aero, and they are a pleasure to work with. They have an authorized service center here in the US (Austin, TX), but I understand that they may be looking for a new US service center.
Is that enough info for you?
All the best to you in your search,
Welcome to the Hybrid int amp world....!! My and many others favourite amps.
Pathos Logos owner.
Howard and Chris,
You have no idea how thankful I am for all this explanation. Honestly, I can't wait to have all the system set up. I will keep you all posted!
PS. Any bananas/brass brands you would recommend? I heard Eichmann are really good.
Well, you guys made it. I spent the whole morning researching tubes online and didn't get any work done. Anyway, this is for the good.
I asked the seller of my MkI and it has a Tesla tube. I did a little searched and it seems they are really similar to the Siemmens.
Nevertheless, I am rather suspicious. Tesla tubes are slightly cheaper than Siemmens (See the following listing: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=67816&item=5754089979&rd=1)
Regardless, I love the man (Tesla), probably the greatest investor of all times. So, I will give them a shot. Needless to say that I will compare them against the Siemmens and the Mullard.
Once again, thanks for everything. Josep
In my other amp, the Tesla had a slightly thinner, more analytical sound than the Siemens. Have not tried it in the Prima Hybrid, however. Try different tubes. The amp takes only one 6922 tube, so you don't have to buy them in pairs. You'll find one that suits you.
Hi everyone, while I am waiting for my MKI to arrive I emailed the Audio Aero guys because I was wondering whether this is a class-A amp or not. Well, they finally replied (to my surprise) saying this is a class-B. (Not even a class AB.) Well, I know there is more to life than class-A and other technical specifications, but can anyone provide some thoughts on this matter? Thanks, Josep
I just purchased this MK I version and it is very good. The used market makes these a steal. I have not heard everything but it is the best that I have heard. It bests
equipment that goes for twice or more of the new price. I was worried about it being only 40 watts but it has more power than I need and I listen to a lot of rock. It will also kick out enough base for rock music, something that some integrateds won't do.
Thank you Boa2.
I just received the MK1. I must say I am really impressed with its performance. The sound is warm and honestly I don't know why you need more than 40W. It makes my Triangles fly! The only thing that surprised me is that it did not have phono stage, but that's fine. I don't even own a turntable. Right now it has the Tesla tube in it and I bought a couple of Mullards and the Siemmens to compare, but I think I'll wait, since it seems that it is pretty tough to open. (It's got many screws...)
In addition, I have to tell you that Audio Aero contacted me again correcting their last email. The amp is AB, apparently it uses the TDA7294 DMOS amp. I guess that just gives me piece of mind. Thank you all for your great advice. Josep
Get yourself a number 2 allen key and take the 7 screws out of the case. Remove the cover by sliding it back a little. Carefully remove the tube so that it does not rock the circuit board to which the socket is attached. Then change that Tesla tube. You will notice a welcome improvement with either of your replacement tubes. Try them both to see which you prefer. Also, that amp doesn't really warm up for about 25 minutes, which you may have already noticed. Enjoy!
Hi, quick question, I am trying ot use the Prima as a preamp. Has anyone try it with McIntosh or Gamut? Can you tell me how to hook it up?
Just go from the "pre out" to your amp.